A catheter of the type mentioned is known in the prior art from, by way of example, U.S. Pat. Nos. 8,932,246 and 8,409,128. It is preferably used in cases of limited cardiac output to support the heart and the blood circulation. In particular, it can also be used in cases of higher-grade aortic insufficiency. It is used to transport the conveyed body fluid from a first location to another location, without increasing the pressure of the fluid at the first location significantly above the physiologically specified state, by utilizing the principle of a submersible pump, and preferably by the use of a balloon catheter combined with the principle of a diaphragm pump, wherein the term ‘submerged pump’ is used to mean a pump which is immersed in the fluid being conveyed, and the term ‘diaphragm pump’ is used to mean a pump with a drive which is separated by a membrane from the fluid being conveyed. Thus it allows, compared to the known method of intra-aortic balloon counterpulsation, a directional transport of the body fluid, as well as less stress on the patient.
Such catheters can be referred to as pump catheters as well. It is possible to use a separate drive in such a pump catheter. The catheter is then, in its basic form, merely a drive-less line catheter. The pump catheter can then be created, for example, by inserting an adjustable displacement device—for example, a balloon catheter of an intra-aortic balloon pump (IABP)—into the internal volume of the catheter after the line catheter has been placed. As such, it is reasonably possible to furnish the catheter without a drive as well.
The complexity, and the stress on the patient, of a minimally invasive insertion of a catheter into the body—for example via groin vessels—substantially depends on the size, particularly the largest outer diameter, of the catheter. Therefore, from the perspective of the patient and the attending physician, it is best for the outer diameter of the catheter to be as small as possible. On the other hand, in order to ensure the required pump power—that is, the volume of fluid to be transported per unit of time—along with the lowest possible loads on the fluid being transported, the largest possible inner diameter—at least in the section of the catheter through which the fluid must be transported—is advantageous.